Researchers at the Johns Hopkins Children's Center and 34 other ophthalmology
centers across North America report that in children with moderate amblyopia,
or "lazy eye," patching the unaffected eye for two hours daily works
just as well as patching the eye for six hours, the standard amblyopia treatment.

The findings, which appear in the May issue of the Archives of Ophthalmology,
will likely change the way doctors treat moderate amblyopia and could lead
to better compliance with treatment and improved quality of life for children
with amblyopia, researchers say. The most common cause of visual impairment
in childhood, amblyopia affects as many as 3 percent of children in the United
States.

In the study, 189 children up to age 7, all with moderate amblyopia, were
randomly assigned to wear an eye patch for two hours or six hours daily for
four months. Both groups of children also performed one hour a day of "near"
work, such as coloring, tracing, reading, and crafts, while their eye was
patched. Children in both groups showed significant improvement in the vision
of the eye with amblyopia, the researchers found.

"After four months, we found that 79 percent of children in the two-hour
group and 76 percent of children in the six-hour group could read at least
two more lines on the standard eye chart, a clear indication that wearing
the patch for just two hours is an effective means of treatment," said
study chairman Michael Repka, M.D., a pediatric ophthalmologist at the Children's
Center and Wilmer Eye Institute at Johns Hopkins.

Repka noted that these findings do not necessarily apply to all children
with amblyopia. "Children with more severe amblyopia, or who have amblyopia
from causes other than crossed eyes or refractive error, may need a different
treatment regimen," he said. "The Pediatric Eye Disease Investigator
Group (PEDIG), which conducted this study, is currently conducting a clinical
trial on children with severe amblyopia and expects the results will be available
this fall."

"Because the daily burden to administer treatment for amblyopia falls
on the parent, the findings from this study will immediately affect families
that have young children with this eye disorder," he added. "The
findings make it much easier for parents to monitor their children and encourage
children to successfully comply with treatment. Timely and successful treatment
for amblyopia in childhood can prevent lifelong visual impairment."

Having the child perform one hour of "near" work per day while
wearing an eye patch was an important part of the prescribed treatment, Repka
said. However, it remains unclear if the same amount of visual improvement
would occur with patching alone. "We are planning a clinical trial to
address the importance of near work in the treatment of amblyopia," he
said.

Amblyopia, which usually begins in infancy or childhood, is a condition of
poor vision in an otherwise healthy eye because the brain has learned to favor
the other eye. Although the eye with amblyopia often looks normal,
there is interference with normal visual processing that limits the development
of a portion of the brain responsible for vision. The most common causes of
amblyopia are crossed or wandering eyes or significant differences in refractive
error, such as farsightedness or nearsightedness, between the two eyes. Without
treatment compliance in early childhood, visual impairment can persist into
adulthood.

Patching the unaffected eye has been the mainstay of amblyopia treatment
for decades. In March 2002, Hopkins researchers also reported the effectiveness
of a second treatment, using atropine eye drops that dilated the unaffected
eye, temporarily blurring vision. Both treatments force the child to use the
eye with amblyopia, stimulating vision improvement in that eye by helping
the part of the brain that manages vision to develop more completely.

However, with patching, opinions among ophthalmologists varied widely on
the number of daily hours it should be prescribed. No prior study had provided
conclusive evidence of the optimal number of patching hours.

This research was conducted by the PEDIG at 35 clinical sites throughout
North America. The PEDIG focuses on studies of childhood eye disorders that
can be implemented by both university-based and community-based practitioners
as part of their routine practice. The study was funded by the National Eye
Institute, National Institutes of Health, and the U.S. Department of Health
and Human Services.